Ignition system



April 23, 1968 H. TUGGLE IGNITION SYSTEM Filed Feb. 9, 1966 'IIIIIIIIIIIIII4 lwwcvzzor LLOYD h 77/ 645 5 MMMWM United States Patent 3,379,181 lGNlTlQN SYSTEM Lloyd H. Toggle, Galesbnrg, Ill., assignor to Outboard Marine Corporation, Waukegan, Ill., a corporation of Delaware Filed Feb. 9, 1966, Ser. No. 526,216 8 Ciaims. (Cl. 123-41465) ABSTRACT OF THE DISCLQSURE member through an element which is radially movable in response to variation in rotational speed.

This invention relates to ignition systems, and more particularly, to ignition systems for internal combustion engines.

An object of the invention is to provide an ignition system for an internal combustion engine, which ignition system affords interruption of primary circuit current flow without using conventional breaker points.

Another object of the invention is to provide an ignition system for an internal combustion engine, which ignition system is efiicient, has a long life, has few moving parts, and can be economically manufactured.

Another object of the invention is to provide an ignition system which is of the type referred to above and which includes means for changing the time of interruption of current flow in the primary circuit in accordance with the speed of operation of the engine.

In accordance with the invention, the ignition system includes a primary circuit having a source of power for affording current flow in the primary circuit, a primary coil, a rotatable member electrically connected to a ground, a brush electrically connecting the rotatable member to the primary coil, and means on the rotatable member and traversed by the brush for affording interruption of current flow in the primary circuit in response to rotation of said member.

More specifically, the brush is disposed to engage the periphery of the rotatable member and is biased toward the rotatable member by a suitable spring. The means on the rotatable member for affording interrruption of the current flow in the primary circuit comprises a first insert carried in a notch or groove in the periphery of the rotatable member by insulating means. Thus, when the brush travels from the peripheral surface of the rotatable member and breaks contact with the rotatable member, the current in the primary circuit is interrupted and the engine spark plug is fired.

Means are provided for changing the time of interruption of current flow in the primary circuit relative to the time of arrival of the piston at top dead center. Said means includes a second insert of electrically conducting material disposed adjacent to the first insert in said notch in the rotatable member and insulated from the rotatable member and the first insert by insulating means. Said means further includes means normally electrically connecting said second insert to said rotatable member, said connecting means being operable upon rotation of said engine above a pre-determined speed to break the electrical connection of said second insert to said rotatable member whereby said second insert serves as a primary circuit current interrupter. Thus, depending upon the direction of rotation of said rotatable member, said second insert is effective to interrupt current flow in said primary circuit prior to interruption thereof by the first insert.

Other objects, advantages and features will become apparent from the following description and accompanying drawings in which:

FIGURE 1 is a partially broken away and sectioned View of an ignition system used with an internal combustion engine and embodying various of the features of the invention;

FIGURE 2 is a fragmentary view similar to FIGURE 1 showing the ignition system in a changed condition;

FIGURE 3 is an enlarged view taken along line 33 of FIGURE 2;

FIGURE 4 is a cross sectional view taken along line 4-4 of FIGURE 1; and

FIGURE 5 is a schematic view of the ignition system shown in FIGURE'I.

Referring to the drawings and more particularly to FIGURE 1, the ignition system of the invention is generally identified by the numeral and is used in conjunction with an internal combustion engine 12, fragmentarily shown in FIGURE 1.

The ignition system 10 broadly includes a primary circuit 14 and a secondary circuit 15. The primary circuit 14 (shown schematically in FIGURE 5) includes a suitable source of power, such as a magneto 18 shown in the illustrated embodiment. The magneto 18 operates in a conventional manner and includes a three leg laminated iron core 19 having a primary coil 16 and a secondary coil 17 wound on the center leg 20 in a conventional manner. Rotation of the polar shoes 21 of magnet 22 past the core 19 induces a current in the primary circuit 14. Interruption of current flow in the primary circuit 14 induces a high voltage in the secondary coil 17 and ultimately in the secondary circuit 15. The high voltage fires a spark plug 22 which is electrically connected to the secondary coil 17 in a conventional manner.

A rotatable member 24 is fixed to a shaft 26 which is rotated by the engine 12. The rotatable member 24 is of electrically conducting material and may be the flywheel of the engine 12, in which case the shaft 26 would be the crankshaft of the engine 12. The rotatable member is grounded by a suitable ground 27 (shown schematically in FIGURE 1).

Means are provided for electrically connecting the rotatable member 24 as part of the primary circuit 14 to afford current flow through the rotatable member 24. In the preferred embodiment, said means comprises a contacting member or carbon brush 28 carried in a suitable bracket 30 which is fixed to the engine 12 proximate the rotatable member 24. The contacting member 28 is biased into engagement with the rotatable member 24 by a suitable spring 32 carried in the bracket 30 and is disposed to engage an annular surface 36 on the rotatable member 24. Adjusting screw 34 is provided for changing the bias of the spring 32.

Means are provided on the rotatable member 24 for affording interruption of current flow in the primary circuit 14 in timed relation to the operation of the engine. In the preferred embodiment, the interrupting means (schematically shown in FIGURE 5 and identified by the letter A) comprises a first current interrupting or nonconducting means in the form of a first insert or element 38 carried in a suitable groove or notch on the annular surface 36 of the rotatable member 24. The insert 38 is preferably made of the same material as the rotatable member 24 so as to have the same weight per volume as the rotatable member and thereby to insure rotational 3 balance of the member 24. If desired, the groove 40 can be open to the face 31 (see FIGURE 3) of the rotatable member 24.

The insert 38 is electrically insulated from the rotatable member 24 by insulating means which also forms a part of said first current interrupting means. Various insulating means can be employed and in the preferred embodiment said insulating means comprises a plastic or nylon member 50 (see FIGURES 3 and 4) which is disposed between the insert 38 and the rotatable member 24. The insert 38 is fixed to the insulating member 50 which in turn is fixed to the rotatable member 24 by any suitable electrically non-conducting means. Said insulating means further includes spacing the insert 38 from the walls of the groove 40 of the rotatable member 24 by air gaps 54 and 55 transverse of the direction of rotation of the member 24 and by an air gap 56 between the insert 38 and the bottom of the groove 40.

Upon rotation of member 24 in a counterclockwise direction, as shown by the arrow in FIGURE 1, current flow in the primary circuit is interrupted when the contacting member 28 disengages and therefore breaks contact with the rotatable member 24 and fully engages the first current interrupting means, as shown in FIGURE 1. The spark plug 22 will fire when this occurs. The duration of the primary circuit current interruption is determined by the engine speed as well as by the length of the non-conducting insert 38 plus the width of air gaps 54 and 55.

A condenser 53 is connected across the interrupting means (see FIGURE 5 for schematic representation) to prevent sparking or arcing between the contacting member or brush 28 and the rotatable member 24.

Means are provided for automatically changing the time of interruption of current flow in the primary circuit 14 in timed relation to speed of the engine 12. Said means generally comprises a second current interrupting means which is selectively operable, depending upon engine speed, to interrupt primary circuit current flow prior to interruption thereof by said first current interrupting means. Said second current interrupting means comprises a conducting means in the form of a second insert or contact 60 of electrically conducting material mounted in the groove 40 which is sutficiently elongated to receive the insert 60. The second insert 60 is electrically insulated from the rotatable member 24 and from the first insert 38 by insulating means which form a part of said second current interrupting means. Various insulating means can be employed and in the preferred embodiment said insulating means comprises the nylon insulator 50 which extends the length of the groove 40 and to which the insert 60 is fixed. Said insulating means further includes spacing the insert 60 from the first insert 38 by the air gap 55 which is common to the inserts 38 and 60, together with spacing the insert from the walls of the groove 40 by a transverse air gap '62 and by an air gap 72 which is an extension of the air gap 56.

Said automatic means further includes means on the conducting means for normally electrically connecting the conducting means and the rotatable member 24 and for electrically disconnecting said contact from said rotatable member upon increasing rotation. In the preferred embodiment said means comprises a groove or blind hole 70 located in the second insert 60 and opening into the air gap 72. A spring 74 is housed in the groove 70, and a contacting ball 76 is normally biased by spring 74 into engagement with the rotatable member 24 to afford electrical connection of the second insert 60 with the rotatable member 24 through the ball 76 and spring 74, which are both made of electrically conducting material.

When the rotatable member 24 is rotated above the predetermined speed, the "ball 76 is displaced, under the action of centrifugal force, against the biasing force of the spring 74 from engagement with the rotatable member 24 to thereby break the electrical connection of the second insert 60 with the rotatable member 24, whereby the second insert ti is completely insulated from the rotatable member 24 by insulating means in the form of the air gaps 55, 62, 72 and the nylon member 50. Thus, upon rotation of the rotatable member 24 in a counterclockwise direction, as shown by the arrow in FIGURE 1, current in the primary circuit 14 is interrupted when the contacting member 28 breaks contact with the rotatable member 24 and fully engages the second current interrupting means, as shown in FIGURE 2. When the engine 12 is operating above said predetermined speed such current interruption is efiected by the second current interrupting means and occurs prior to the current interruption atfordable by the first current interrupting means, thus effecting an advance of primary circuit current interruption with concomitant advance in spark plug firing.

In the preferred embodiment, the primary circuit current is interrupted by the second current interrupting means 20 in advance of the first current interrupting means or, in other terms, the included central angle between air gaps and 62 is 20. The duration of primary circuit current interruption in the advance condition is determined by the rotational speed of the engine 12 and the length of the inserts 38 and including the width of air gaps 54, 55 and 62.

The width of each transverse air gaps 54, 55 and 62 is smaller than the width or thickness of the contacting member 28 so that the latter can bridge the gaps and thereby insure smooth and unimpeded rotation of the rotatable member 24.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

1. An ignition system for an internal combustion engine, said ignition system comprising a primary circuit including a source of power for affording current flow in said primary circuit, a primary coil, a grounded rotatable member driven by said engine, a brush connecting said rotatable member and said primary coil, and means on said rotatable member traversed by said brush for affording interruption of current flow in said primary circuit in response to rotation of said member, said current interrupting means including non-conducting means disposed on said rotatable member for engagement by said brush to afford current flow interruption in said primary circuit upon engagement of said brush with said non-conducting means, said rotatable member including a groove and said non-conducting means including a first insert which is disposed in said groove and insulated from said rotatable member by insulating means and which has approximately the same weight per volume as said rotatable member.

2. An ignition system in accordance with claim 1 wherein said insulating means includes a nylon member fixed to said rotatable member and carrying said first insert, together with air gaps surrounding the remainder of said insert and including at least one transverse air gap.

3. An ignition system for an internal combustion engine, said ignition system comprising a primary circuit in cluding a source of power for affording current flow in said primary circuit, a primary coil, a grounded rotatable member driven by said engine, a brush connecting said rotatable member and said primary coil, first means on said rotatable member traversed by said brush for affording interruption of current flow in said primary circuit in response to rotation of said member, and means on said rotatable member for automatically changing the time of interruption of current flow in the primary circuit comprising electrically conducting means electrically insulated from said rotatable member and from said first current interrupting means, and means on said conducting means normally electrically connecting said conducting means and said rotatable member, said means normally electrically connecting said conducting means and said rotatable member being movable upon rotation of said rotatable member above a predetermined speed to afford breaking of said electrical connection of said conducting member to said rotatable member whereupon current flow in said primary circuit is interrupted upon engagement of said contacting member with said second current interruptings means.

4. An ignition system in accordance with claim 3 wherein said rotatable member includes a notch and said conducting means of said second current interrupting means includes a second insert carried in said notch, said second insert having therein a groove and being insulated from said rotatable member and said first insert by insulating means, and wherein said means normally electrically connecting said conducting means and said rotatable member includes a spring received in said groove, a ball partially received in said groove and baised into engagement with said rotatable member by said spring to aflord normal electrical connection of said second insert to said rotatable member, whereupon rotation of said rotatable member above said predetermined speed affords movement of said ball, against the biasing force of said spring, out of engagement with said rotatable member to break the electrical connection of said second insert with said rotatable member whereby said second current interrupting means is efiective to interrupt current flow in said primary circuit prior to interruption thereof by said first current interrupting means.

5. An internal combustion engine having a fly-wheel including thereon a notch, a first metallic insert carried on said rotatable fly-wheel and in said notch, said first insert being electrically insulated from said rotatable fiy- Wheel, a second metallic insert carried in said notch proximate said first metallic insert, said second metallic insert being electrically insulated from said rotatable fly-wheel and from said first metallic insert, said second metallic insert including a groove, a spring carried in said groove, and a ball carried in said groove and biased by said spring into engagement with said rotatable fly-wheel to afford electrical connection of said second metallic insert to said fly-wheel, a primary circuit including a source of power for affording current flow in said primary circuit, a primary coil, a brush carried on said engine proximate said fly-wheel and electrically connected to said coil, a spring biasing said brush into engagement with said fly-wheel, thereby electrically connecting said fiy-wheel and said primary coil so that said rotatable member forms a part of said primary circuit, said brush engaging said first and second metallic inserts upon rotation of said fly-whecl whereby, upon rotation of said engine below a predetermined speed, said brush engages said first insert to afiord interruption of current flow in said primary circuit and upon rotation of said engine above a predetermined speed, said ball is moved out of engagement with said fly-wheel and contact of said brush with said second insert affords interruption of current flow in said primary circuit.

6. An ignition system for an internal combustion engine, said ignition system comprising a primary circuit including a source of power for affording current flow in said primary circuit, a primary coil, a rotatable member, a brush electrically connected to said primary coil and engageable with said rotatable member, first means on said rotatable member traversed by said brush and electrically disconnected from said rotatable member, for interrupting primary circuit current flow, second means on said rotatable member traversed by said brush, and means operable to electrically disconnect said second means from said rotatable member in response to rotation of said engine above a predetermined speed for interrupting primary circuit current flow in advance of the primary circuit current flow interruption aiforded by said first means.

7. An ignition system for an internal combustion engine, said ignition system comprising a primary circuit including a source of power for affording current flow in said primary circuit, a primary coil, a rotatable member driven by said engine, a brush connecting said rotatable member and said primary coil, a spring biasing said brush for engagement with said rotatable member, a first insert disposed on said rotatable member for engagement by said brush and means including transverse air gaps electrically insulating said first insert from said rotatable member, whereby current interruption in said primary circuit is afforded upon full engagement of said brush with said first insert upon rotation of said member, a second insert disposed on said rotatable member proximate said first insert for engagement by said brush, means including transverse air gaps electrically insulating said second in sert from said rotatable member and from said first insert, a contacting ball carried on said second insert, and means biasing said ball radially inward into contact with said rotatable member for normally electrically connecting said second insert to said rotatable member, whereby upon rotation of said rotatable member above a predetermined speed, said ball is displaced radially outwardly from contact with said rotatable member so that current flow in said primary circuit is interrupted upon said brush fully engaging said second insert and thereby to automatically change the time of interruption of current iiow in said primary circuit.

8. An ignition system for an internal combustion engine, said ignition system comprising a primary circuit including a source of power for affording current flow in said primary circuit, a primary coil, a grounded rotatable member driven by said engine, a brush electrically connecting said rotatable member and said primary coil, and means on said rotatable member traversed by said brush for affording interruption of current flow in said primary circuit in response to rotation of said rotatable member, said means on said rotatable member traversed by said brush including an element on said rotatable member traversed by said brush and electrically insulated from said rotatable member, a contact located on said rotatable member in electrically insulated relation to said rotatable member and in trailing adjacent relation to said element with respect to the direction of rotation of said rotatable member, and means for electrically connecting said contact to said rotatable member during rotation of said member below a given speed and for electrically disconnecting said contact from said rotatable member upon increasing rotation above said given speed so as to automatically advance the time of interruption of current flow in said primary circuit.

References Cited UNITED STATES PATENTS 1,221,176 4/1917 Herzog et al l23l46.5 2,753,490 7/1956 Smits 31070 2,843,769 7/ 1958 McGrevy 123-149 LAURENCE M. GOODRIDGE, Primary Examiner. 

